In recent decades, the air-conditioning industry has been developed rapidly, thus a heat exchanger, as one of the main components of the air conditioner, is also required to be improved to optimize the design according to the market requirements. A parallel flow heat exchanger has characteristics, such as a high cooling efficiency, a small size and a light weight, thus can meet the market requirements quite well, and it has been increasingly applied in various kinds of air conditioning systems in recent years.
A parallel flow heat exchanger mainly includes micro-channel flat tubes, fins and header pipes. The header pipes are provided at two ends of the micro-channel flat tubes to distribute and collect refrigerant. The corrugated or louvered fins are provided between adjacent micro-channel flat tubes to improve the heat exchange efficiency between the heat exchanger and the air. A baffle is provided inside the header pipe to divide all of the micro-channel flat tubes into a plurality of flow paths, and with reasonable distribution of flat tubes in each flow path, a better heat exchange efficiency may be realized.
FIGS. 1 to 4 are schematic views of a heat exchanger to be improved which is known by the inventors, a heat exchanger 100′ includes a first header pipe 1′, a second header pipe 2′, a third header pipe 3′, a fourth header pipe 4′, a plurality of flat tubes 5′, and fins 6′ welded between every two adjacent flat tubes 5′. The first header pipe 1′ includes a first baffle 10′ located inside the first header pipe 1′ to separate the first header pipe 1′ into a first space 11′ and a second space 12′. The first baffle 10′ is an imperforate baffle, thus the first space 11′ is not in direct communication with the second space 12′. Similarly, the third header pipe 3′ includes a second baffle 30′ located inside the third header pipe 3′ to separate the third header pipe 3′ into a third space 31′ and a fourth space 32′. The second baffle 30′ is also an imperforate baffle, thus the third space 31′ and the fourth space 32′ are not in direct communication with each other.
Reference is made to FIGS. 3 and 4. Arrows in the figures indicate flow directions of the refrigerant. The flow of the refrigerant in the heat exchanger 100′ substantially includes four flow paths.
In a first flow path, the refrigerant enters into the first space 11′ of the first header pipe 1′ from a refrigerant inlet, and due to the separation of the first baffle 10′, the refrigerant flows along corresponding flat tubes 5′ to the second header pipe 2′ in the direction of the downward arrows.
In a second flow path, the refrigerant entering into the second header pipe 2′ flows along corresponding flat tubes 5′ to the second space 12′ of the first header pipe 1′ in the direction of the upward arrows.
In a third flow path, due to the communication between the second space 12′ of the first header pipe 1′ and the third space 31′ of the third header pipe 3′, and the separation of the second baffle 30, the refrigerant passing through the first header pipe 1′ flows along corresponding flat tubes 5′ to enter into the fourth header pipe 4′ in the direction of the downward arrows.
In a fourth flow path, the refrigerant entering into the fourth header pipe 4′ flows along corresponding flat tubes 5′ to the fourth space 32′ of the third header pipe 3′ in the direction of the upward arrows, and finally is discharged via a refrigerant outlet.
Referring to FIG. 5, with intensive research and creative efforts, the inventors have found that the first flow path to the fourth flow path have different heat exchange performances, wherein the first flow path, the second flow path, the fourth flow path have a low heat exchange performance while the third flow path have a heat exchange performance much better than that of other flow paths.
Therefore, an urgent technical issue to be addressed in this technical field is to improve the heat exchange performance of the heat exchanger on the whole according to heat exchange performances of different flow paths.